Yesterday, in a fairly short, largely unanimous Supreme Court decision, Justice Clarence Thomas delivered an opinion–Mcfadden v. United States–answering a simple question: how much knowledge is necessary to convict someone under Section 841(a)(1) of the Controlled Substance Act when the controlled substance in question is a drug analogue? 

Chief Justice John Roberts concurred in part, and concurred in the judgement.

The Analogue Act of 1986 identifies a category of substances substantially similar to those listed on the federal controlled substance schedules, then instructs the courts to treat them as controlled substances if they’re intended for human consumption.  In turn, Section 841(a)(1) of the Controlled Substance Act (CSA) makes it unlawful to “knowingly manufacture, distribute, or possess with intent to distribute controlled substances.”

In the opinion, Justice Thomas holds that Section 841(a)(1) of CSA requires government to establish that the defendant knew he or she was dealing with a “controlled substance.” When the substance is an analogue, the knowledge requirement is satisfied:

  • if the defendant knew the substance was controlled under CSA or the Analogue Act, even if the identity of the substance was unknown, or,
  • if the defendant knew the identity of the substance he or she possessed, even without knowledge that it was a “controlled” substance. After all, “ignorance of the law is typically not a defense.”

Previously, the Fourth Circuit Court of Appeals had approved a jury instruction that didn’t accurately convey these knowledge requirements. Because of this, their judgement was vacated by this decision and remanded to that court to determine if the error was harmless. If it’s found that the error was not harmless, McFadden would receive a retrial.

This decision is a win for the principle of mens rea–the mental state of a person during the commission of a crime. Traditional common law holds that a person’s guilt hinged not solely on the actual commission of a crime, but also whether or not it was intentional. As such, mens rea is generally viewed in criminal law as a necessary element to establish. This decision simply clarifies government’s future responsibility to show that a person knowingly committed an offense pursuant to the CSA or the Analogue Act, by establishing one of the two knowledge requirements.